Acids and Bases

// =============================================================================
// 1. DATA LOADER
// =============================================================================
acidBaseData = {
  // Define the path to your new JSON file.
  // IMPORTANT: You will need to create this file and adjust the path.
  const jsonFilePath = "../files/json/acids-bases.json"; 
  
  const response = await fetch(jsonFilePath);
  if (!response.ok) {
    throw new Error(`HTTP error! status: ${response.status} - Could not load ${jsonFilePath}`);
  }
  return await response.json();
}

// =============================================================================
// 2. HELPER FUNCTION
// =============================================================================
function shuffle(array) {
  const newArray = [...array];
  for (let i = newArray.length - 1; i > 0; i--) {
    const j = Math.floor(Math.random() * (i + 1));
    [newArray[i], newArray[j]] = [newArray[j], newArray[i]];
  }
  return newArray;
}

// =============================================================================
// 3. CSS STYLING
// =============================================================================
html`
<style>
  .acid-base-widget {
    max-width: 600px; margin: 2rem auto; padding: 1.5rem 2rem;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: #fdfdfd; border-radius: 12px;
    border: 1px solid #e2e8f0; 
  }
  .ab-card-front {
    background: white; border-radius: 8px; border: 1px solid #e2e8f0;
    padding: 2rem; text-align: center; min-height: 120px;
    display: flex; flex-direction: column; justify-content: center; align-items: center; gap: 1rem;
  }
  .ab-substance { font-size: 2.5rem; font-weight: 600; color: #1e293b; }
  .ab-question { font-size: 1.25rem; color: #475569; font-weight: 500; }
  
  .ab-choices { 
    display: grid; 
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
    margin-top: 1.5rem;
  }
  .ab-choices button {
    font-size: 1rem; font-weight: 600; padding: 0.75rem 1rem;
    border-radius: 8px; border: 2px solid; cursor: pointer; transition: all 0.2s ease;
  }
  .ab-btn-strong-acid { background-color: #fef2f2; border-color: #f87171; color: #b91c1c; }
  .ab-btn-strong-acid:hover { background-color: #fee2e2; }
  .ab-btn-weak-acid { background-color: #fff7ed; border-color: #fb923c; color: #9a3412; }
  .ab-btn-weak-acid:hover { background-color: #fed7aa; }
  .ab-btn-strong-base { background-color: #eff6ff; border-color: #60a5fa; color: #1d4ed8; }
  .ab-btn-strong-base:hover { background-color: #dbeafe; }
  .ab-btn-weak-base { background-color: #f0f9ff; border-color: #7dd3fc; color: #0369a1; }
  .ab-btn-weak-base:hover { background-color: #e0f2fe; }

  .ab-card-back {
    background-color: #f7f9fc; border: 1px solid #dbe3f0; border-radius: 8px;
    opacity: 0; max-height: 0; overflow: hidden; transition: all 0.5s ease-in-out;
    margin-top: 1.5rem;
  }
  .ab-card-back.visible { opacity: 1; max-height: 500px; padding: 1.5rem; }
  
  .feedback-header { display: flex; align-items: center; gap: 0.75rem; font-size: 1.5rem; font-weight: 600; margin-bottom: 1rem; }
  .feedback-correct { color: #047857; }
  .feedback-incorrect { color: #b91c1c; }
  .feedback-icon { font-size: 1.8rem; }

  .feedback-answer-text { font-size: 1.1rem; margin-bottom: 1rem; line-height: 1.6; }
  .feedback-note-label { font-weight: 600; color: #475569; margin-bottom: 0.5rem; }
  .feedback-note-text { background: white; padding: 1rem; border-radius: 6px; border: 1px solid #e2e8f0; }

  .ab-controls { display: flex; justify-content: center; margin-top: 1.5rem; border-top: 1px solid #e2e8f0; padding-top: 1.5rem; }
  .ab-btn-next {
      font-size: 1rem; font-weight: 600; padding: 0.75rem 1.5rem;
      border-radius: 8px; border: 2px solid #c7d2fe; cursor: pointer; transition: all 0.2s ease;
      background: #eef2ff; color: #4338ca;
  }
  .ab-btn-next:hover { background-color: #e0e7ff; }
</style>
`

// =============================================================================
// 4. REACTIVE STATE
// =============================================================================
mutable appState = ({
  deck: [], // Start with an empty deck
  index: 0,
  quizMode: 'formula', // 'formula' or 'name'
  userAnswer: null, // null, 'correct', or 'incorrect'
  showAnswer: false
});

// =============================================================================
// 5. DATA INITIALIZER (Corrected to Filter Comments)
// =============================================================================
{
  // This line makes this cell reactively dependent on `acidBaseData`.
  // It will only run AFTER the fetch is complete.
  acidBaseData;

  // This logic now runs only when the data is ready and the deck is still empty.
  if (appState.deck.length === 0 && acidBaseData && acidBaseData.length > 0) {
    
    // We filter the array to include only objects that have a `formulaHTML` property.
    // This removes all the `{ "comment": "..." }` objects.
    const filteredDeck = acidBaseData.filter(card => card.formulaHTML);
    
    // Now, we shuffle the CLEAN, filtered deck.
    mutable appState = { ...appState, deck: shuffle(filteredDeck) };
  }
  
  // This cell produces no visible output.
  return html``;
}

// =============================================================================
// 6. MAIN APPLICATION RENDERER
// =============================================================================
{
  if (appState.deck.length === 0) {
    return html`<div class="acid-base-widget"><div class="ab-card-front">Loading cards...</div></div>`;
  }

  const currentCard = appState.deck[appState.index];

  // --- Event Handlers ---
  const handleAnswer = (type, strength) => {
    const isCorrect = (type === currentCard.type && strength === currentCard.strength);
    mutable appState = {
      ...appState,
      userAnswer: isCorrect ? 'correct' : 'incorrect',
      showAnswer: true
    };
  };
  
  const handleNextCard = () => {
    const nextIndex = (appState.index + 1) % appState.deck.length;
    mutable appState = {
      ...appState,
      index: nextIndex,
      userAnswer: null,
      showAnswer: false
    };
  };

  // --- Create the main HTML node ---
  const widgetNode = html`
    <div class="acid-base-widget">
      
      <div class="ab-card-front">
        <div class="ab-substance">${appState.quizMode === 'formula' ? currentCard.formulaHTML : currentCard.name}</div>
        <div class="ab-question">How would you classify this substance?</div>
      </div>
      
      <div class="ab-choices" style="display: ${appState.showAnswer ? 'none' : 'grid'};">
        <button class="ab-btn-strong-acid" data-type="acid" data-strength="strong">Strong Acid</button>
        <button class="ab-btn-strong-base" data-type="base" data-strength="strong">Strong Base</button>
        <button class="ab-btn-weak-acid" data-type="acid" data-strength="weak">Weak Acid</button>
        <button class="ab-btn-weak-base" data-type="base" data-strength="weak">Weak Base</button>
      </div>
      
      <div class="ab-card-back ${appState.showAnswer ? 'visible' : ''}">
        ${appState.userAnswer === 'correct' ? html`
          <div class="feedback-header feedback-correct"><span class="feedback-icon">✓</span> Correct!</div>` : ''}
        ${appState.userAnswer === 'incorrect' ? html`
          <div class="feedback-header feedback-incorrect"><span class="feedback-icon">✗</span> Not quite.</div>` : ''}
        
        <div class="feedback-answer-text">
          <strong>${currentCard.name} (${currentCard.formulaHTML})</strong> is a <strong>${currentCard.strength} ${currentCard.type}</strong>.
        </div>
        
        <div class="feedback-note-label">Note:</div>
        <div class="feedback-note-text">${currentCard.notes}</div>
      </div>
      
      <div class="ab-controls" style="display: ${appState.showAnswer ? 'flex' : 'none'};">
        <button class="ab-btn-next" data-action="next">Next Card</button>
      </div>
      
    </div>
  `;
  
  // --- Attach all event listeners ---
  widgetNode.querySelectorAll('.ab-choices button').forEach(btn => {
    btn.addEventListener('click', () => handleAnswer(btn.dataset.type, btn.dataset.strength));
  });

  const nextBtn = widgetNode.querySelector('[data-action="next"]');
  if (nextBtn) {
    nextBtn.addEventListener('click', handleNextCard);
  }

  return widgetNode;
}